body {
    margin: 0;
    background-color: #000;
    background-image: radial-gradient(ellipse at top,
            #335476 0.0%, #31506e 11.1%, #304b67 22.2%, #2f4760 33.3%,
            #2d4359 44.4%, #2c3f51 55.6%, #2a3a4a 66.7%, #293643 77.8%,
            #28323d 88.9%, #262e36 100.0%);
    height: 100vh;
    overflow: hidden;
    font-family: monospace;
    font-weight: bold;
    letter-spacing: 0.06em;
    color: rgba(255, 255, 255, 0.75);
}

#c {
    display: block;
    touch-action: none;
    transform: translateZ(0);
}

/*/////////////////////
//        HUD        //
/////////////////////*/
.hud__score,
.pause-btn {
    position: fixed;
    font-size: calc(14px + 2vw + 1vh);
}

.hud__score {
    top: 0.65em;
    left: 0.65em;
    pointer-events: none;
    user-select: none;
}

.cube-count-lbl {
    font-size: 0.46em;
}

.pause-btn {
    position: fixed;
    top: 0;
    right: 0;
    padding: 0.8em 0.65em;
}

.pause-btn>div {
    position: relative;
    width: 0.8em;
    height: 0.8em;
    opacity: 0.75;
}

.pause-btn>div::before,
.pause-btn>div::after {
    content: '';
    display: block;
    width: 34%;
    height: 100%;
    position: absolute;
    background-color: #fff;
}

.pause-btn>div::after {
    right: 0;
}

.slowmo {
    position: fixed;
    bottom: 0;
    width: 100%;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.4s;
    will-change: opacity;
}

.slowmo::before {
    content: 'SLOW-MO';
    display: block;
    font-size: calc(8px + 1vw + 0.5vh);
    margin-left: 0.5em;
    margin-bottom: 8px;
}

.slowmo::after {
    content: '';
    display: block;
    position: fixed;
    bottom: 0;
    width: 100%;
    height: 1.5vh;
    background-color: rgba(0, 0, 0, 0.25);
    z-index: -1;
}

.slowmo__bar {
    height: 1.5vh;
    background-color: rgba(255, 255, 255, 0.75);
    transform-origin: 0 0;
}

/*/////////////////////
//       MENUS       //
/////////////////////*/
.menus::before {
    content: '';
    pointer-events: none;
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background-color: #000;
    opacity: 0;
    transition: opacity 0.2s;
    transition-timing-function: ease-in;
}

.menus.has-active::before {
    opacity: 0.08;
    transition-duration: 0.4s;
    transition-timing-function: ease-out;
}

.menus.interactive-mode::before {
    opacity: 0.02;
}

/* Menu containers */
.menu {
    pointer-events: none;
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    user-select: none;
    text-align: center;
    color: rgba(255, 255, 255, 0.9);
    opacity: 0;
    visibility: hidden;
    transform: translateY(30px);
    transition-property: opacity, visibility, transform;
    transition-duration: 0.2s;
    transition-timing-function: ease-in;
}

.menu.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    transition-duration: 0.4s;
    transition-timing-function: ease-out;
}

.menus.interactive-mode .menu.active {
    opacity: 0.6;
}

.menus:not(.interactive-mode) .menu.active>* {
    pointer-events: auto;
}

/* Common menu elements */
h1 {
    font-size: 4rem;
    line-height: 0.95;
    text-align: center;
    font-weight: bold;
    margin: 0 0.65em 1em;
}

h2 {
    font-size: 1.2rem;
    line-height: 1;
    text-align: center;
    font-weight: bold;
    margin: -1em 0.65em 1em;
}

.final-score-lbl {
    font-size: 5rem;
    margin: -0.2em 0 0;
}

.high-score-lbl {
    font-size: 1.2rem;
    margin: 0 0 2.5em;
}

button {
    display: block;
    position: relative;
    width: 200px;
    padding: 12px 20px;
    background: transparent;
    border: none;
    outline: none;
    user-select: none;
    font-family: monospace;
    font-weight: bold;
    font-size: 1.4rem;
    color: #fff;
    opacity: 0.75;
    transition: opacity 0.3s;
}

button::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background-color: rgba(255, 255, 255, 0.15);
    transform: scale(0, 0);
    opacity: 0;
    transition: opacity 0.3s, transform 0.3s;
}

/* No `:focus` styles because this is a mouse/touch game! */
button:active {
    opacity: 1;
}

button:active::before {
    transform: scale(1, 1);
    opacity: 1;
}

.credits {
    position: fixed;
    width: 100%;
    left: 0;
    bottom: 20px;
}

a {
    color: white;
}

/* Only enable hover state on large screens */
@media (min-width: 1025px) {
    button:hover {
        opacity: 1;
    }

    button:hover::before {
        transform: scale(1, 1);
        opacity: 1;
    }
}